The stress corrosion cracking (SCC) behavior of 2024-T351 aluminium alloy in acid NaCl solution was studied by using the electrochemical noise technique. The electrochemical noise signal was recorded during the immersion test of the Wedge Opening Loading (WOL) specimen in the Zero Resistance Ammeter (ZRA) mode. The characteristic parameters were analyzed in time and frequency domains, respectively. The results indicate that SCC process of AA2024-T351 is not continuous. The current noise could be used to analyze the nucleation and propagation processes of SCC. During the nucleation period of SCC, the transient peaks could be observed, which was characterized by the small fluctuation amplitude of the current noise. This implies that the alternating film rupture and re-passivation process is dominant on the specimen surface. With the immersion time increasing, the characteristic peaks are observed. It is indicated that the crack propagation occurs. Meanwhile, the amplitude of the characteristic peaks increases and the periodic character could also be observed. The wavelet decomposition provides a strong tool to distinguish the nucleation and propagation processes of SCC according to the different current energy distribution.